Immunological and Anti-bronchoconstrictive Properties of the Anti-Asthma Formula ASHMI in a Murine Model of Asthma

Introduction. Asthma is a world-wide health concern. The disease is characterized by episodic exacerbation of airway constriction and pulmonary inflammation. The Anti-Asthma TCM formula ASHMI has shown to be efficacious as monotherapy in humans and murine models of asthma. We sought to address mechanisms underlying the immunological and anti-bronchoconstrictive effects of the formula in a murine model of asthma.;Methods. Ovalbumin allergic mice were generated by systemic sensitization with ovalbumin followed by tracheal ovalbumin challenges. For evaluation of ASHMI immunological effects mice were orally treated with ASHMI for 6 weeks. After completion of therapy mice were challenged with ovalbumin and airway hyperreactivity and pulmonary inflammation was evaluated. Cytokine levels in bronchoalveolar lavage fluid and splenocyte cultures were measured. For mechanistic studies some mice were given ASHMI treatment in conjunction with neutralizing antibodies for IFN-gamma or TGF-beta. For assessment of anti-bronchoconstrictive effects, a single dose of ASHMI was given 2 hours prior to antigen or acetylcholine challenge and subsequent airway function measurements were performed. For myography experiments, tracheal rings from asthmatic or naive mice were evaluated for contraction to acetylcholine in the presence and absence of ASHMI, with or without beta2-antagonist ICI11855, Indomethacin or EP2/EP4 and IP receptor antagonists. cAMP and PGE2/PGI2 levels in tracheal rings were measured by ELISA. Relaxation to exogenous PGE2 was also studied. Regulation of tracheal contractility by ASHMI individual herb extracts, solvent fractions of ASHMI, Sophora flavescens or matrine alkaloids was also investigated.;Results. ASHMI provided persistent protection from asthma pathology which was IFN-gamma but not TGF-beta dependent. ASHMI-treated mice displayed sustained suppression of Th2-cyokines and ovalbumin-specific IgE. ASHMI exerted direct effects on airway function evidence by beneficial effects of a single acute dose. Tracheal ring contractility was reduced in a 2-agonist independent but PGE-2 dependent manner. ASHMI-mediated inhibition contraction appeared to be mediated by its component herb S. flavescens and matrine alkaloids were found to be potent inhibitors of tracheal responses to acetylcholine.;Conclusions. These data support the argument for ASHMI being a comprehensive alternative therapy for asthma with beneficial effects on asthmatic immune responses and airway function.